1. Field of the Invention
The present invention relates to an in-feed type centerless grinding apparatus.
2. Description of the Related Art
For example, the centerless grinding apparatuses used for manufacturing the rollers of rolling bearings are classified into an in-feed type, a through-feed type and a tangential-type.
According to the in-feed type, a work is ground in a predetermined shape by radially feeding a grinding wheel or a regulating wheel in a state where the work is set in a grinding space between the rotating grinding wheel and the rotating regulating wheel.
Conventionally, the outer diameter surface and the end surface of a work are ground by separate grinding apparatuses, respectively, in a manner that the work subjected to the heat treatment is first ground at its outer diameter surface and then ground at its end surface. Further, as to a work required for a high accuracy, in order to obtain the sufficient accuracy of the end surface serving as the reference at the time of grinding the outer diameter surface, the end surface is ground after grinding the outer diameter surface and further the outer diameter surface is subjected to the finish grinding.
JP-B-62-58870 and Japanese Patent No 2678144 disclose a technique for simultaneously grinding the outer diameter surface and the inner diameter surface of an annular work.
JP-A-6-339842 discloses an apparatus for grinding the inner diameter surface and the end surface of an annular work. This apparatus is arranged in a manner that a grinding wheel for grinding the inner diameter surface is disposed at a first grinding processing position and a grinding wheel for grinding the end surface is disposed at a second grinding processing position, whereby a work is sequentially indexed at the two grinding processing positions thereby to sequentially grind the inner diameter surface and the end surface.
There has been desired a grinding apparatus which can simultaneously grind the outer diameter surface and the end surface of a work so that the rollers of a rolling bearing etc. can be ground quickly.
None of JP-B-62-58870 and Japanese Patent No 2678144 discloses a technique for grinding the end surface of a work.
According to the apparatus described in JP-A-6-339842, although both the inner diameter surface and the end surface of the work can be processed with one-time chucking, it is impossible to simultaneously grind both the outer diameter surface and the end surface of the work since a chuck interferes with the grinding wheel.